Electronics
A. Ebadiyan; A. Shokri; M. Amirmazlaghani; N. Darestani Farahani
Abstract
Background and Objectives: Semiconductor junction-based radioisotope detectors are commonly used in radioisotope batteries due to their small size and excellent performance. This study aims to design a betavoltaic battery based on a metal-porous semiconductor Schottky structure, comprising an N-type ...
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Background and Objectives: Semiconductor junction-based radioisotope detectors are commonly used in radioisotope batteries due to their small size and excellent performance. This study aims to design a betavoltaic battery based on a metal-porous semiconductor Schottky structure, comprising an N-type zinc oxide (ZnO) semiconductor and platinum (Pt) metal. Methods: we utilized the TCAD-SILVACO 3D simulator to simulate the device, and a C-Interpreter code was applied to simulate the beta particle source, which was an electron beam with an average energy equivalent to 63Ni beta particles. The short circuit current, open-circuit voltage, fill factor (FF), and efficiency of the designed structure were calculated through simulation. Additionally, we discussed the theoretical justification based on the energy band structure. Results: The energy conversion efficiency of the proposed structure was calculated to be 11.37% when bulk ZnO was utilized in the Schottky junction. However, by creating pores and increasing the effective junction area, a conversion efficiency of 35.5% was achieved. The proposed structure exhibited a short-circuit current, open-circuit voltage, and fill factor (FF) of 37.5 nA, 1.237 V, and 76.5%, respectively.Conclusion: This study explored a betavoltaic device with a porous structure based on a Schottky junction between Pt and ZnO semiconductor. The creation of pores increased the contact surface area and effectively trapped beta beams, resulting in improved performance metrics such as efficiency, short circuit current, and open-circuit voltage.
Electronics
A. Shokri; M. Amirmazlaghani
Abstract
Background and Objectives: The Field-effect Bipolar Junction Transistor (FEBJT) is a device with a bipolar junction transistor (BJT) characteristics except that it is designed with standard CMOS technology. Therefore, it can be implemented in nanometer dimensions without the usual restrictions in fabricating ...
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Background and Objectives: The Field-effect Bipolar Junction Transistor (FEBJT) is a device with a bipolar junction transistor (BJT) characteristics except that it is designed with standard CMOS technology. Therefore, it can be implemented in nanometer dimensions without the usual restrictions in fabricating the nanoscale BJTs. In addition to the advantages that FEBJT has as a bipolar junction transistor in analog circuits, it can also be used to design digital circuits. Here, we have investigated the capability of FEBJT as the base of a new digital family in nanometer scales.Methods: To do this, we have designed and simulated an inverter logic gate based on FEBJT. We have presented this logic gate's static and dynamic assessment criteria and compared these characteristics with other technologies. Also, a three-stage ring oscillator circuit based on FEBJT is designed and presented. A three-dimensional TCAD Mixed-Mode simulator has been used for the simulations.Results: The value of maximum frequency, PDP, dynamic power, and ring frequency are calculated 0.25THz, 38×10-17 J, 94uW, and 85GHz, respectively.Conclusion: The excellent function of the FEBJT-based inverter gate and oscillator demonstrates that this device can be used as the base of new digital circuits and can open a doorway to the nanoscale CMOS digital family.
A. Sotoudeh; A. Rajabi; M. Amirmazlaghani
Volume 5, Issue 1 , January 2017, , Pages 71-77
Abstract
In this paper, photodetection properties of a Graphene-based device at the third telecommunication window have been reported. The structure of the device is a Graphene-silicon Schottky junction which has been simulated in the form of an infrared photodetector. Graphene has specific electrical and optical ...
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In this paper, photodetection properties of a Graphene-based device at the third telecommunication window have been reported. The structure of the device is a Graphene-silicon Schottky junction which has been simulated in the form of an infrared photodetector. Graphene has specific electrical and optical properties which makes this material a good candidate for optoelectronic applications. Photodetection characteristic of Graphene-silicon Schottky junction is investigated by measuring the (current-voltage) curve at the third telecommunication window under 1550nm radiations. The DC electrical characteristic of the device is calculated. The simulated rectifier junction has a potential barrier of 0.31eV, the ideality factor of 2.7 and the saturation current of 10-11A. The detector responsivity under 1550nm radiations is measured about 20mA/W which is an order of magnitude larger than other Si-based detectors in this wavelength. The internal quantum efficiency (QEin) is calculated about 60% while the external quantum efficiency (QEex) is measured to be 1.6%. A comprehensive theoretical justification is presented based on Fowler theory which allows comparison between the simulation results and the theoretical predictions. For simulating Graphene, a user-defined material is introduced to TCAD-SILVACO software which includes all electrical and optical properties of this novel 2D material. Graphene optical properties, specifically at near-IR region(up to 2um wavelength), have been extracted from the real measurement results. Graphene is a Si-compatible material which can provide a sensitive IR detector integrated with other Si-based devices
